Plural armature bidirectional stepper



Aug. 20, 1968 w. KocH PLURAL ARMATURE BIDIRECTIONAL STEPPER 2 Sheets-Sheet l Filed Jan. 24, 1966 FIG.3.

Aug. 20, 1968 w. KOCH 3,398,303

PLURAL ARMATURE BIDIRECTIONAL STEPPER Filed Jan. 24, 1966 2 Sheets-Sheet 2 United States Patent Olce 3,398,303 Patented Aug. 20, 1968 3,398,303 PLURAL ARMATURE BIDIRECTIONAL STEPPER Wilhelm Koch, Buxtehude, Germany, assignor to National Rejectors Inc., St. Louis, Mo., a corporation of Missouri Filed Jan. 24, 1966, Ser. No. 522,513 7 Claims. (Cl. 310-22) This invention relates to improvements in moneyhandling devices. More particularly, this invention relates to improvements in stepping motors for credit-accumulating mechanisms which can be -used in money-handling devices.

It is, therefore, an object of the present invention to provide an improved stepping motor for -a creditaccumulating mechanism which can be used in a moneyhandling device.

Credit-accumulating mechanisms for money-handling devices frequently have rotatable elements that can be stepped up to accumulate credits corresponding to the value of the money introduced into those money-handling devices; and the rotatable elements of Isome of those credit-accumulating mechanisms can be stepped down to deduct credits corresponding to the value of the products or services dispensed by those money-handling devices. Such credit-accumulating mechanisms are Very useful; but many of those money-handling devices are bulky and costly. It would be desirable to provide a credit-accumulating mechanism which had a rotatable element that could be stepped up to accumulate credits and that could be stepped down to deduct credits and which was compact and inexpensive. The present invention makes it possible to provide such a credit-accumulating mechanism; and it does so by providing a stepping motor which has a rotatable shaft that can be rotated in step-by-step fashion in one direction and that can be rotated in step-by-step fashion iu the opposite direction and which is compact and inexpensive. It is, therefore, an object of the present invention to provide a stepping motor which has a rotatable shaft that can be rotated in step-by-step fashion in one direction and that can be rotated in step-by-step fashion in the opposite direction and which is compact and inexpensive.

Other and further objects and advantages of the present invention should become apparent from an examination of the drawing and accompanying description.

In the drawing and accompanying description a preferred embodiment of the present invention is shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and do not limit the invention and that the invention will be defined by the appended claims.

In the drawing,

FIG. 1 is an elevational view of a credit-accumulating mechanism which includes one preferred embodiment of stepping motor that is made in accordance with the principles and teachings of the present invention,

FIG. 2 is an elevational view of the right-hand end of the credit-accumulating mechanism of FIG. 1,

FIG. 3 is a sectional view, on an enlarged scale, through the central portion of the credit-accumulating mechanism of FIG. l, and it is taken along the plane indicated by the line 3 3 in FIG. 1,

FIG. 4 is a sectional view on the scale of FIG. 3, through part of the credit-accumulating mechanism of FIG. 1, and it is taken along the plane indicated by the line 4 4 in FIG. 3,

FIG. 5 is a sectional View on the scale of FIG. l, through part of the credit-accumulating mechanism of FIG. 1, and it is taken along the plane indicated by the line 5 5 in FIG. 3,

FIG. 6 is a sectional view which is similar to that of FIG. 5, but it shows the credit-accumulating mechanism in an actuated position,

FIG. 7 is a sectional view, on the scale of FIG. 3, through part of the credit-accumulating mechanism of FIG. 1, and it is taken along the plane indicated by the line 7 7 in FIG. 6,

FIG. 8 is a further sectional view on the scale of FIG. 3, through the credit-accumulating mechanism of FIG. l, and it is taken along the plane indicated by the line 8 8 in FIG. 3,

FIG. 9 is a sectional view, on the scale of FIG. 3, through the part of the credit-accumulating mechanism shown in FIG. 8, and it is taken along the plane indicated by the line 9 9 in FIG. 8,

FIG. l0 is an elevational view on the scale of FIG. 3, of part of the structure shown in FIG. 8, and it is taken along the plane indicated by the line 10 10 in FIG. 8,

FIG. 1l is a further sectional view, on the scale of FIG. 3, through the part of the credit-accumulating device shown in FIG. 8, it is taken along the plane indi cated by the line 11 11 in FIG. 8, and it shows that part in partially actuate position,

FIG. 12 is a view which is similar to that of FIG. 10, but it shows the said part of the credit-accumulating mechanism in its partially actuated position,

FIG. 13 is another elevational view of the part of the credit-accumulating mechanism shown in FIG. l0,

FIG. 14 is a view which is similar to that of FIG. ll, but it shows the said part of the credit-accumulating mechanism in its fully actuated position,

FIG. l5 is a view which is simliar to that of FIG. 12 but it shows the said part of the credit-accumulating mechanism in its fully actuated position, and

FIG. 16 is a perspective view, on the scale of FIG. 3, of the said part of the credit-accumulating mechanism.

Referring to the drawing in detail, the numeral 20 denotes the base for a credit-accumulating mechanism that includes a preferred embodiment of stepping motor which is made in accordance with the principles and teachings of the present invention. A wall 22 projects upwardly from one edge of the base 20; and that wall and that base can be bent from a stili sheet of metal. Large openings 24, 26 and 28 in the Wall 22 define strutlike portions 23. Three bosses 30 project outwardly from the wall 22; and those bosses are disposed adjacent the outer ends of the strut-like portions 23. The bosses 30 are provided with threaded sockets.

A boss 32 projects outwardly from the wall 22 adjacent the inner ends of the strut-like portions 23. That boss has an opening 34 therein; and the axis of that opening is perpendicular to the plane defined by the wall 22. A shaft 36 is rotatably mounted within the opening 34 in the boss 32; and that shaft extends outwardly beyond both ends of the boss 32. A spiral torsion spring 38, which is rectangular in cross section, has the inner end thereof secured to the shaft 36 by a pin 40, as shown particularly by FIG. 3. The turns of that spring are guided and confined by a circular plate 44 which has an annulus 46 thereon; and that plate and that annulus coact to define a cup-like housing for that spring. That housing is normally closed by a circular plate 42; and screws 48 normally hold that circular plate in assembled relation with that housing. The outer end of the spring 38 extends through an opening 47 in the annulus 46, as shown particularly by FIG. 4; and hence the ends of that spring are iixedly secured to the shaft 36 and to the cup-like housing for that spring. A pin 50 is secured to the circular plate 44, and that pin projects into the opening 24 in the wall 22; and the restorative forces within the spring 38 will hold that pin in engagement with the strut-like portion 23 between the openings 24 and 28, as shown by FIG. 4.

3 Those restorative forces also will tend to rotate the shaft 36 in the clockwise direction in FIGS. 1 and 4.

The numeral 52 denotes a sleeve of insulation which is telescoped over that part of the shaft 36 which extends to the right of the boss 32, as that boss is viewed in FIG. 3; and that sleeve of insulation will rotate as a unit with that shaft. A larger diameter sleeve 53 of insulation is telescoped over the sleeve 52; and the `sleeve 53 carries a set screw 54 which can be tightened, against the sleeve 52 to cause the sleeve 53 to rotate las a unit with the shaft 36. An arm 56, of a resilient conductive metal such as Phosphor bronze, has a loop at the inner end thereof which telescopes loosely over the sleeve 52 and has a bifurcated outer end. A similar arm 58 has a loop at the inner end thereof which loosely telescopes over the sleeve 52 and has a bifurcated outer end. The arm 56 abuts one face of the sleeve 53 While the arm S8 abuts the other face of that sleeve. Rivets 60, one of which is shown in FIG. 3, mechanically connect the arms 56 and 58 to the `sleeve 53 and also electrically connect those arms. If desired, a conductor 57 can have the ends thereof intimately bonded to the arms S6 and 58, by solder or the like, to additionally electrically connect the arms 56 and 58. The arms 56 and 58 constitute a movable contact for the credit-accumulating mechanism; and that movable contact is generally denoted by the numeral 59. An elongated flexible conductor 61 is intimately bonded to the arm 56, and that conductor will be connected to a suitable binding post or solder termin-al, not shown, for the creditaccu'mulating mechanism. That elongated exible conductor will preferably be wound loosely around the boss 32 in the form of a couple of turns of a spiral so it can permit the movable contact 59 to rotate more than three hundred and `sixty degrees without being halted or blocked by that elongated llexible conductor. A closure 62 has a recess therein which telescopes over the outer end of the sleeve 52 of insulation held 0n the outer portion of the shaft 36. That closure can be secured to the sleeve 52 of insulation by a press fit, by an adhesive, or the like.

The numeral 64 denotes an annulus of insulation which has ears 66 projecting outwardly therefrom; and those ears have openings therein which are in register with the threaded sockets in the bosses 30. Machine screws 68 extend through the openings in the ears 66 and into the threaded sockets in the bosses to xedly hold the annulus 64 in spaced rel-ation to the wall 22. The annulus 64 is concentric with the shaft 36; and it has two sets of stationary contacts 70 and 72 which form two annuli that are concentric with that shaft. Each stationary contact 70 and each stationary contact 72 has a portion which extends inwardly of the annulus 64 and has `a portion which extends outwardly of that annulus. The outer portions of the stationary contacts 70 and 72 can have conductors secured to them. Each stationary contact 70 is wide enough to provide a full electrical contact with the bifurcated outer end of the arm 56, but adjacent stationary contacts 70 are spaced apart suicient distances to keep that bifurcated outer end from engaging more than one stationary contact 70 at a time. Similarly, each stationary contact 72 is wide enough to provide a full electrical contact with the bifurcated outer end of the arm 58, but adjacent contacts 72 are spaced apart suflicient distances to keep that bifuracted outer end from engaging =more than one stationary contact 72 at a time. The stationary contacts 70 and 72 are set in register with each other so a stationary contact 72 will be engaged by the Kbifurcated outer end of the arm 58 whenever a stationary contact 70 is engaged by the bifuracted outer end of the arm 56.

A sleeve 76 is telescoped over that portion of the shaft 36 which extends to the left of the housing for the spring 38, as that housing is viewed in FIG. 3; land that sleeve can rotate freely relative to that shaft. A ratchet wheel 78 is fxedly secured to that sleeve adjacent one end thereof, and an escapement wheel 80 is xedly secured to that sleeve adjacentthe other end thereof. The sleeve 76 will xedly hold the wheels 78 land 80 against rotation relative to each other, but will permit those wheels to rotate readily relative to the shaft 36.

A mounting bracket 82 is secured to the wall 22 of the right of the wheels 78 and 80, as those wheels' are viewed in FIG. 1. A resilient pawl 84 is secured to that mounting bracket by a machine screw, and that pawl will engage the teeth on the -ratchet wheel 78 to prevent clockwise rotation of that ratchet wheel in FIGS. 1, 5 and 6. However, that pawl will permit that ratchet wheel 78 to be rotated in the counterclockwise direction in FIGS. 1, 5 and 6-the free end of that pawl raising upwardly as the inclined faces of the teeth on that ratchet wheel move relative to it. A fixed stop and guide 86 is secured to, and depends downwardly from, the mounting bracket 82; and the lower end of that stop and guide inclines downwardly and to the right as shown by FIGS. 5 and 6.

The numeral 88 denotes a bracket for an electromagnet; and that bracket is secured to the base 20, as shown by FIG. 1. That electromagnet has a coil 90, an armature 92, and a spring 94 which normally urges that armature away from that coil. However, whenever the coil 90 is energized, it will overcome the force of the spring 94 and pull the armature 92 into the actuated position shown 'by FIG. 6. An L-shaped bracket 96 is secured to the free end of the armature 92, as shown particularly by FIG. 7; and that L-shaped bracket has a threaded opening therein to accommodate part of the shank of a screw 104 which serves as a pivot for a pawl 98. An ear is formed on the lower end of the pawl 98; and a spring 182, which is wound around the screw 104, has one end thereof bearing against the ear 180 and has the other end thereof bearing against the bracket 96.

That spring urges the upper end of the pawl 98 toward the teeth on the ratchet wheel 78, but it can yield to permit that upper end of that pawl to move outwardly and downwardly relative to those teeth. The armature 92 and the L-shaped bracket 96 and the screw 104 normally hold the upper end of the pawl 98 in register with the lower end of the stop and guide 86, as shown by FIG. 5. When the armature 92 is moved downwardly to the actuated position, shown in FIG. 6, the upper end of the pawl 98 will be moved downwardly relative to the ratchet wheel 78 and relative to the stop and guide 86; and the inclined face of the tooth against which that upper end was resting will force that pawl to rotate slightly in the clockwise direction until that upper end has moved downwardly below the inclined face of that tooth. Thereupon, the upper end of the pawl 98 will -move into engagement with the back of that tooth. Subsequently, when the coil 90 is again de-energized, the returning spring 94 of the electromagnet will force the pawl 98 to move upwardly into engagement with the stop and guide 86; and it will force the ratchet wheel 78 to rotate in the counterclockwise direction in FIGS. 1, 5 and 6 an angular distance equal to the angular width of one tooth as it does so.

The numeral denotes a bracket, which is shown particularly by FIG. 8; and that bracket has a hub 112 which is telescoped over the shaft 36. A set screw 114 carried lby that hub can be set in `engagement with thatshaftto prevent relative rotation between that bracket and that shaft. A notch 116 is formed in the left-hand end of the bracket 110, as that bracket is viewed in FIG. 8. Ears 118 project from the left-hand end of the bracket 110; and those ears have openings therein t0 receive a pivot 119 in the form of an elongated pin.

An escapement lever 120 has ears 124 at the left-hand end thereof; and those ears have openings therein to accommodate the pivot 119. The ears 124 are elongated to space the escapement lever 120 from the end of the shaft 36, as shown particularly by FIG. 9. A notch 122 is formed in the left-hand end of the escapement lever 120, as shown particularly by FIG. 1; and that notch is generally in register with the notch 116 in the bracket 110.

A spring 121 is wound around the pivot 119, and one end of that spring is hooked around the lower ear 124 on the escapement lever 120 while the other end of that spring is hooked around the left-hand edge of the bracket 110. That spring biases the escapement lever 120 for clockwise rotation in FIG. 9 about the pivot 119.

An ear 125 is formed on the right-hand end of the escapement lever 120, as that lever is viewed in FIG. 9; and a plate 126, a spacer 132, and a plate 134 are secured to the underface of that ear, as those plates and that ear are viewed in FIG. 10. Each of the plates 126 and 134 and the spacer 132 is considerably thinner than the space between adjacent teeth on the escapement wheel 80. As a result, the distance from the upper face of the plate 134 to the bottom face of the plate 126 is less than the distance between adjacent teeth on the scapement wheel 80, as shown by FIG. 10.

The plate 134 is generally L-shaped in coniigurationhaving a leg portion that abuts the bottom face of the ear 125 on the lever 120 and having a foot portion that extends outwardly beyond the ear 125 and which can be moved into the spaces between adjacent teeth on the escapement wheel 80. The spacer 132 is generally trapezoidal in configuration; and it is largely overlain by the ear 125 on the lever 120 and by the leg portion of the plate 134. However, the outer edge of the spacer 132 projects outwardly beyond the outer edges of the ear 125 and of the leg portion of the plate 134 to abut the adjacent face of the escapement wheel 80, as shown by FIG. 14. The engagement between the outer face of the spacer 132 and the adjacent face of the escapement wheel 80 limits the counterclockwise rotation of the lever 120 in FIG. 9. The plate 126 has a notch 128 therein which can permit the teeth on the escapement wheel 80 to move past that plate plate without engaging that plate. The plate also has an ear 130 which is coextensive with a part of the outer face of the escapement wheel 80 and which can engage that part of that face, as shown by solid lines in FIG. 9, to limit clockwise rot-ation of the lever 120. The portion 129 of the plate 126 intermediate the notch 128 and the ear 130 can move into the spaces between adjacent teeth on the escapement wheel 80. The lever 120, the plates 126 and 134, and the spacer 132 constitute an escapement mechanism which can rotate about the pivot 119, between the solid-line and dotted-line positions in FIG. 9, to permit the spiral spring 38 to rotate that escapement mechanism and the bracket 110 and the shaft 36 in the clockwise direction in FIG. 1.

The numeral 136 denotes a bracket for an electromagnet; and that bracket is secured to the rear face of the wall 22. That bracket supports a coil 138 and an armature 140; and a helical extension spring 146 urges thearmature 140 to the position shown by FIG. 2. An extension 142 1s ysecured to the armature 140; and that extension carries a pin 144 and holds that pin generally in register with the axis of the shaft 36. The extension 142 on the armature 140 is oifset intermediate the ends thereof to normally space the pin 144 from the escapement lever 120, as shown by FIG. 2 and by the solid lines in FIG. 9. However, when the coil 138 is energized, the armature 140 and the extension 142 thereof will force the pin 144 to move to the dotted-line position in FIG. 9, and thus torce the escapement lever 120 to move into the dotted-line posltion shown in FIG. 9.

The shaft 36, the spring 38, the sleeve 76 and its ratchet wheel 78 and escapement wheel 80, the pawls 84 and 86, the Iescapement lever 120, and the two electromagnets constitute a stepping motor. That stepping motor can lstep the shaft 36 in -both directions, and yet that stepplng motor is compact and inexpensive. As the shaft 36 is stepped, 1t will move the movable contact 59 relative to the stationary contacts 70 and 72.

The upper end of the pawl 98 will normally abut a tooth on the ratchet wheel 78 and the lower end of the fixed guide and stop 86. As a result, that pawl will normally be held against lateral movement, and thus will normally 'be unable to move out of the path of the teeth on the ratchet wheel 78. Consequently, the pawl 98 will normally hold the ratchet wheel 78, and hence the sleeve 76 and the escapement wheel 80, against rotation. This is desirable because it will keep sharp blows, that may be applied to the money-handling device in which the credit-accumulating mechanism of FIG. l is mounted, from changing the position of that ratchet wheel. Also, the pawl 98 and the fixed stop and guide 86 are useful in keeping the ratchet wheel 78 from moving further than desired in the counterclockwise direction. Speciiically, the fixed stop and guide 86 is mounted so it will halt upward movement of the pawl 98 after that pawl has moved far enough to advance the ratchet wheel 78 an angular distance greater than the angular width of one tooth 'but less than the angular widths of two teeth.

In using the credit-accumulating mechanism of FIG. 1, one side of a suitable source of electric power will be connected to the binding post, not shown, to which the iiexible conductor 61 is connected; and appropriate stationary contacts 70 and 72 will be connected to electrically-actuated components in the money-handling device with which that credit-accumulating mechanism will be used. For purposes of illustration, it will be assumed that each stationary contact 70 and each stationary Contact 72 represents a credit of five cents. Further, it will be assumed that a selection switch and an electrically-responsive component of the money-handling device are connected to the thirty-eighth stationary contact 70 and that a further selection 4switch and electrically-responsive component of that moneyhandling device are connected to the thirty-ninth stationary contact 72. The coil 90 of the credit-accumulating electromagnet will -be suitably connected to switches that are provided in the money-handling device and that can respond to the insertion of a nickel to provide one energization of that coil, can respond to the insertion of a dime to provide two successive Ienergizations of that coil, can respond to the insertion of -a quarter to provide tive successive energizations of that coil, can respond to the insertion of a half dollar to provide ten successive energizations of that coil, and can respond to the insertion of a dollar to provide twenty successive energizations of that coil. Such switches are known in the art .and are not, per se, part of the present invention. The coil 138 ofthe creditdeducting electromagnet will be connected to a mechanism within the money-handling device which will energize that coil each time a product or service is dispensed or change is paid out, and which will energize that coil the exact number of times needed to match the sales price of the product or service that is dispensed plus the amount of change, if any, that is dispensed to the patron. Such mechanisms are known in the art .and are not, per se, part of the present invention.

If a patron inserts a nickel, the coil 90 of the creditaccumulating electromagnet will become energized and will move the armature 92 from the normal position shown in FIG. 5 to the actuated position shown in FIG. 6. That movement will move the pawl 98 downwardly, and, since the iiexible pawl 84 prevents clockwise rotation of the ratchet wheel 78, the spring 102 will yield to permit the pawl 98 to rotate far enough in the clockwise direction to move past the inclined face of the tooth against which it had been resting, and to move downwardly until it is below the rear face of that tooth. When the coil 90' is subsequently de-energized, the returning spring 94 of the electromagnet will force the pawl 98 to move upwardly to the position shown by FIG. 5. As that pawl moves upwardly, it will force the tooth against which the upper end thereof bears to move upwardly until the upper end of that pawl again engages and is held by the lower end of the stop and guide 86. The rotation of the ratchet wheel 78 will force the sleeve 76 and the escapement wheel to rotate in the counterclockwise direction. Because the spring 121 normally 7 holds the portion 129 of the plate 126 in the space between two adjacent teeth on the escapement wheel 80, the counterclockwise rotation of that wheel will normally force the escapement lever 120, the bracket 110, and the shaft 36 to rotate in that direction. The rotation of that shaft will force the arms 56 and 58 of the movable contact 59 to rotate in the counterclockwise direction and thus move into engagement with the first stationary contact 70 and the first stationary contact 72.

If a dime is then inserted, the coil 90 of the creditaccumulating electromagnet will receive two successive pulses; and it will respond to those pulses to move the armature 92 from the normal position of FIG. S to the actuated position of FIG. 6, will permit that a-rmature to return to the position of FIG. 5, will again move that armature from the position of FIG. to the position of FIG. 6, and will then again permit that armature to return to the position of FIG. 5. Each time that armature is moved from the position of FIG. 5 to the position of FIG. 6 it will cause ythe upper end of the pawl 98 to move downwardly along the face of a tooth on the ratchet wheel 78 until it drops into position behind that tooth; and each time that armature is moved from the position of FIG. 6 to the position of FIG. 5 it will cause the pawl 98 to move upwardly and move the ratchet wheel 78 in the counterclockwise direction an angular distance equal to the angular width of one tooth. As that ratchet wheel is moved twice in the counterclockwise direction, it will cause the escapement wheel 80, the escapement level 120, the bracket 110, the shaft 36, and the movable contact 59 to rotate in the counterclockwise direction an angular distance corresponding to the angular widths of two teeth on the ratchet wheel 78. This means that the arms 56 and 58 will come to rest in engagement with the third stationary contacts 70 and 72.

If a quarter is then inserted, the coil 90 will receive ve successive pulses; and it will respond to those pulses to move the armature 92 from the position of FIG. 5 to the position of FIG. 6 then back again a total of ve times. The ratchet wheel 78, the escapement wheel 80, the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 will be rotated in the counterclockwise direction an angular distance corresponding to the angular widths of five teeth on that ratchet wheel; and the arms 56 and 58 will come to rest in engagement with the eighth contacts 70 and 72.

If a half dollar is then inserted, the coil 90 will receive ten successive pulses; and it will respond to those pulses to move the armature 92 from the position of FIG. 5 to the position of FIG. 6 and then back again a total of ten times. The ratchet wheel 78, the escapement wheel 80, the escapement lever 120, the bracket 110; the shaft 36, and the movable contact 59 will be rotated in the counterclockwise direction an angular distance corresponding to the angular Widths of ten teeth on that ratchet wheel; and the arms 56 and 58 will come to rest in engagement with the eighteenth stationary contacts 70 and 72.

It a dollar is inserted, the coil 90 will receive twenty ksuccessive pulses; and it will respond to those pulses to move the armature 92 from the position of FIG. 5 to the position of FIG. 6 and then back again a total of twenty times. The ratchet wheel 78, the escapement wheel 80, the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 will be rotated in the counterclockwise direction an angular distance corresponding to the angular widths of twenty teeth on the ratchet wheel 78; and the arms 56 and 58 will come to rest in engagement with the thirtyeighth stationary contacts 70 and 72. At this time a credit of one dollar and ninety cents will have been established; and, if the pat-ron actuates the selection switch connected to the thirty-eighth stationary contact 70, he will receive the desired product or service.

As that product or service is dispensed, the moneyhandling device will supply a total of thirty-eight pulses to the coil 138 of the credit-deducting electromagnet of the credit-accumulating mechanism. That coil will respond to each of those pulses to move the armature 140 inwardly and'thus force the pin 144 from the solidline position to the dotted-line position in FIG. 9. As that pin moves into that dotted-line position, it will force the escapement lever 120, to move the plates 126 and 134 from the solid-line positions to the dotted-line positions in FIG. 9; and, as the plate 126 so moves, the portion 129 thereof will move out of the path of the teeth on the escapement wheel and thus permit the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 to start rotating in the clockwise direction in FIG. l. That rotation will be halted very promptly by the plate 134 which moved into the path of the teeth on the escapement Wheel 80 before the portion 129 of the plate 126 moved out of that path. At this time, the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 will have rotated in the clockwise direction in FIG. l an angular distance equal to about one-half of the angular width of a tooth on the escapement wheel 80.

As the coil 138 subsequently becomes de-energized, the returning spring 146 of the credit-deducting electromagnet will move lthe pin 144 out of engagement with the escapement lever 120; and the returning spring 121 will move that escapement lever back to the solid-line position in FIG. 9. As that escapement lever so moves, the portion 129 of the plate 126 will move into the space between the tooth which it originally engaged and the next-succeeding tooth, and then the plate 134 will move out of the path of the teeth on the escapement Wheel 80. Thereupon, the spring 38 will force the portion 129 of the plate 126 into engagement with that nextsucceeding tooth. At this time, the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 will have rotated in the clockwise direction a total angular distance corresponding to the angular width of a tooth on the escapement wheel 80. This means that the arms 56 and 58 will have moved out of engagement, respectively, with the thirty-eighth stationary contacts 70 and 72 and into engagement with the thirty-seventh stationary contacts 70 and 72. While the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 were being rotated in the clockwise direction in FIG. 1, the resilient pawl 84 was holding the ratchet wheel 78, and hence the escapement wheel 80, against rotation in that direction. v

Each actuation of the coil 138 of the credit-deducting electromagnet will cause the movable contact 59 to move in the counterclockwise direction an angular distance equal to the angular Width of a tooth on the escapement wheel 80. Since the angular width of each tooth on that escapement wheel is equal to the angular width of each tooth on the ratchet wheel 78, the thirty-eight actuations of the coil 138 will cause the arms 56 and S8 to move back to their initial position, out of engagement with the first stationary contacts 70 and 72.

If the patron inserts further money after he actuates the selection switch but before the coil 138 of the credit-.deducting electromagnet can step the movable contact 59 back to its zero credit position, the credits corresponding to that further money will not be lost. Specifically, each pulse which is produced as that further money is inserted will cause the coil to step the ratchet wheel 78 in the counterclockwise direction in FIG. 1 an angular distance equal to the angular width of a tooth on that ratchet wheel 78; and the sleeve 7-6 and the escapement wheel 80 also will be stepped in that direction that angular distance. As a result, that escapement wheel, the escapement lever 120, the shaft 36, and the movable contact 59 will be displaced further from their zero positions.

If a pulse is received' by the coil 90' of the credit-accumulating electromagnet before a pulse is received by the coil 138 of the credit-deducting electromagnet, the armature 92 of the credit-accumulating electromagnet will move to the position of FIG. 6 and then back to the position of FIG. to cause the ratchet wheel 78 to move the escapement wheel 80, the escapement lever 120, the bracket 110, the shaft 36 and the movable contact 59 one step in the counterclockwise direction. The immediately succeeding pulse to the coil 138 of the credit-deducting electromagnet will cause the armature 140 to move to its actuated position and then back again, and will thus cause the plates 126 and 134 to move from the solid-line position to the dotted-line position in PIG. 9 and then back again. That movement of those plates will permit the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 to rotate in the clockwise direction relative to the escapement wheel 80 and lthe ratchet wheel 78 an angular distance equal to the angular width of a tooth on that ratchet wheel. This means that the pulse supplied to the coil 90 accumulated a credit, and that the pulse .supplied to the coil 138 deducted a credit, and that both credits are fully accounted for. If a pulse is supplied to the coil 138 before a pulse is supplied to the coil 90, the credit-deducting electromagnet will cause the movable contact 59 to rotate one step in the clockwise direction to deduct one credit, and then the credit-accumulating electromagnet will immediately cause that movable contact to move one step in the counterclockwise direction to accumulate a credit. This means that the proper deduction of a credit will be made and that thereafter the proper accumulation of a credit will be made; and once again both credits will be fully accounted for. If the coils 90 and 138 receive pulses at the same instant, the credit-accumulating electromagnet will rotate the ratchet Wheel 78 and the escapement wheel 80 one step in the counterclockwise direction but the credit-deducting electromagnet Will rotate the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 in the clockwise direction relative to the escapement wheel 80 an angular distance equal to the width of one tooth on the ratchet wheel 78. This means that although the ratchet wheel 78 and the escapement wheel 80 rotated in the counterclockwise direction relative to the stationary contacts 70 and 72, and although the escapement lever 120, the bracket 110, the shaft 36, and the movable contact 59 rotated in the clockwise direction relative to the ratchet and escapement Wheels, the movable contact 59 remained in engagement with the :stationary contacts 70 and 72 which it was engaging before the coils 90 and 138k were pulsed. Here again, both credits will be fully accounted for. All of this means that Whether a credit-accumulating pulse is received by the coil 90 before, after, or while a credit-deducting pulse is being received by the coil 138, the credit-accumulating mechanism of FIG. l will properly respond to, and account for, both of those pulses.

If, when the movable contact 59 reached the thirtyeighth stationary contacts 70 and 72, the patron had not actuated the selection switch connected to the thirty-eighth contact 70, but had inserted a further nickel, the movable contact 59 would have been moved into engagement with the thirty-ninth stationary contacts 70 and 72. That patron can then actuate the selection switch connected to the thirty-ninth lcontact 72; and the money-handling device will dispense the desired product or service, and will then supply thirty-nine successive pulses to the coil 138 of the credit-deducting electromagnet. If no further money is inserted, While that Icoil is responding to those pulses, the movable contact 59 will be moved back to its zero position. However, if additional money is inserted, While that coil is responding to those pulses, the movable contact 59 will not be moved back to its zero position. Importantly, regardless of the amount of money that may be inserted while the coil 138 is being pulsed, the position of the movable contact 59 will, after the pulsing of the coils 90 and 75 138 is completed, correspond exactly to the value of the additional money that was inserted.

The credit-accumulating mechanism of FIG. 1 has two sets of stationary contacts and 72, but either of those sets of contacts can be eliminated. On the other hand, if desired, a further set of stationary contacts could be provided.

The inner end of the pin 144 is rounded, as shown by FIGS. 3 and 9; and that is desirable because it minimizes the frictional forces between that pin and the escapement lever 120. The positioning of the pin 144 so it is generally in register with the axis of the shaft 36 also minimizes the frictional forces between that pin and the escapement lever 120. Consequently, the stepping motor provided by the present invention can have a high eiliciency.

It should be noted that the pin 144 engages the escapement lever intermediate the pivot 119 and the free end of that escapement lever. This provides a desirable multiplying action, and thus permits a moderate movement of the pin 144 to provide the required full movement of the plates 126 and 134.

Whereas the drawing and accompanying description have shown and described a preferred embodiment of the present invention it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the :scope thereof.

What I claim is:

1. A stepping motor that comprises:

(a) a base,

(b) a shaft that is rotatably supported by said base,

(c) said shaft being rotatable in one direction relative to said base and also being rotatable in the opposite direction relative to said base,

(d) means biasing said shaft for rotation in said one direction relative to said base,

(e) a rotatable member that is mounted on, and that can rotate relative to, said rotatable shaft,

(f) an escapement wheel that is rotatable with said rotatable member,

(g) a ratchet wheel that is rotatable with said rotatable member,

(h) a pawl that is mounted adjacent said ratchet wheel and that prevents rotation of said ratchet Wheel, and hence of said rotatable member and escapement wheel, in said one direction but that permits rotation of said ratchet wheel, and hence of said rotatable member and escapement wheel, in said opposite direction,

(i) a second pawl that is mounted adjacent said ratchet wheel,

(j) an electromagnetically-operated element that can be actuated to cause said second pawl to engage a tooth on said ratchet wheel and thereby rotate said ratchet wheel, and hence said rotatable member and escapement wheel, in said opposite direction relative to said base an angular distance substantially equal to the angular width of said tooth,

(k) the rst said pawl yielding to permit said second pawl and said electromagnetically-operated element to rotate said ratchet Wheel, and hence said rotatable member and escapement wheel, in said opposite direction, but thereafter returning to its normal position to block rotation of said ratchet wheel, and hence of said rotatable member and escapement wheel, in said one direction,

(l) a bracket that is secured to said shaft adjacent said escapement wheel and that rotates With said shaft,

(m) an escapement lever that is rotatably secured to said bracket and that rotates with said bracket and said shaft,

(n) one portion of said escapement lever normally being in engagement with said escapement wheel but being movable out of engagement with said escapement Wheel as another portion of said escapment 11 f lever is moved into engagement with said escapement wheel,

(o) said other portion of said escapement lever subsequently moving out of engagement with said escapement wheel as said one portion of said escapement wheel moves back into engagement with said escapement wheel,

(p) the movement of said one portion of said escapement lever out of engagement with said escapement wheel and the movement of said other portion of said escapement lever into engagement with said escapement wheel followed by the movement of said other portion of said escapement lever out of engagement with said escapement wheel and the movement of said one portion of said escapement lever back into engagement with said escapement Wheel permitting said biasing means to move said escapement lever, and hence said bracket and shaft, in said one direction relative to said escapement wheel an angular distance substantially equal to the angular width of a tooth on said ratchet wheel,

(q) a second electromagnetically-operated element that can be seletcively actuated to move said escapement lever relative to said escapement wheel and thereby enable said biasing means to move said escapement lever, and hence said bracket and shaft, in said one direction relative to said escapement wheel an angular distance substantially equal to the angular width of a tooth on said ratchet wheel,

(r) said biasing means and said escapement lever and said bracket and said escapement wheel coacting to permit step-by-step rotation of said shaft in said one direction relative to said rotatable member and to prevent rotation of said shaft in said opposite direction relative to said rotatable member,

(s) said bracket, said escapement lever and said escapement wheel normally holding said shaft and said rotatable member against relative rotation,

(t) whereby actuation of the rst said electromagnetically-operated element will rotate said ratchet wheel and said rotatable member and said escapement wheel in said opposite direction relative to said base and will thereby normally rotate said shaft in said opposite direction relative to said base,

(u) the first said electromagnetically-operated element acting, whenever it is actuated, to move said ratchet wheel, and hence said rotatable member and said escapement wheel, in said opposite direction relative to said base an angular distance substantially equal to the angular width of a tooth on said ratchet wheel irrespective of any actuation of said second electromagnetically-operated element,

(v) said second electrom-agnetically-operated element acting, whenever it is actuated, to effect rotation of said escapement lever, and hence said bracket and shaft, in said one direction relative to said escapement wheel an angular distance substantially equal to the angular width of a tooth on said ratchet wheel irrespective of any actuation of the rst said electromagnetically-operated element,

(w) whereby said stepping motor can respond to pulses applied to said electromagnetically-operated elements even where said pulses yoverlap in point of time,

(X) said shaft having the position thereof substantially unchanged when said electromagnetically-operated elements are actuated simultaneously.

2. A stepping motor as claimed in claim 1 wherein said rotatable member is a sleeve that is telescoped over said shaft, said ratchet wheel and said escapement wheel being fixedly secured to said rotatable member, and said escapement wheel has teeth thereon, the angular Widths of the teeth on said escapement wheel being substantially equal to the angular widths of the teeth on said ratchet wheel.

3. A stepping motor as claimed in claim 1 wherein said escapement lever is rotatably secured to said bracket at one side of said escapement Wheel and said portions of said escapement lever are disposed adjacent the opposite side of said escapement wheel, part of said escapement lever being substantially in register with the axis of said shaft, said second electromagnetically-actuated element having a portion thereof that engages said part of said escapement lever to move said escapement lever relative to said escapement wheel and thereby enable said biasing means to move said escapement lever, and hence said bracket and shaft, in said one direction relative to said escapement wheel an angular distance substantially equal to the angular Width of a tooth on said ratchet wheel, said portion of said second electromagnetically-operated element being substantially in register with said axis of said shaft, and thereby minimizing the area 0f engagement, and hence the frictional losses, between said escapement lever and said second electromagnetically-operated element.

4. A stepping motor that comprises:

(a) a rotatable shaft,

(b) said shaft being rotatable in one direction and also being rotatable in the opposite direction,

(c) a spring biasing said shaft for rotation in said one direction,

(d) a rotatable member that is mounted on, and that can rotate relative to, said rotatable shaft,

(e) an escapement wheel that is rotatable with said rotatable member,

(f) a ratchet wheel that is rotatable With said rotatable member,

(g) a pawl that is mounted adjacent said ratchet wheel and that prevents rotation of said ratchet Wheel, and hence of said rotatable member and escapement wheel, in said one direction but that permits rotation of said ratchet Wheel, and hence of said rotatable member and escapement wheel, in said opposite direction,

(h) a second pawl that is mounted adjacent said ratchet wheel,

(i) a stop adjacent said second pawl,

(j) an electromagnetically-operated element that can be actuated to cause said second pawl to engage a tooth on said ratchet wheel and thereby rotate said ratchet wheel, and hence said rotatable member and escapement wheel, in said opposite direction an angular distance substantially equal to the angular width of said tooth,

(k) the rst said pawl yielding to permit said second pawl and said electromagnetically-operated element to rotate said ratchet wheel, and hence said rotatable member and escapement Wheel, in said opposite direction, but thereafter returning to its normal position to block rotation of said ratchet wheel, and hence of said rotatable member and escapement wheel, in said one direction,

(l) an escapement mechanism that is mounted adjacent said escapement Wheel and that can be actuated to permit said spring to step said shaft in said one direction,

(m) a second electromagnetically-operated element that can be selectively actuated to actuate said escapement mechanism and thereby enable said spring to move said shaft in said one direction relative to said escapement wheel an angular distance substantially equal to the angular width of a tooth on said ratchet wheel,

(n) said spring and said escapement mechanism coacting to permit step-by-step rotation of said shaft in said one direction relative to said rotatable member and to prevent rotation of said shaft in said opposite direction relative to said rotatable member,

(o) said escapement mechanism and said escapement wheel normally holding said shaft and said rotatable member against relative rotation,

(p) whereby actuation of the rst said electromagnetically-operated element will rotate said ratchet wheel and said rotatable member and said escapement wheel in said opposite direction and will thereby normally rotate said shaft in said opposite direction,

(q) the first said electromagnetically-operated element acting, whenever it is actuated, to move said ratchet wheel, and hence said rotatable member and said escapement wheel, in said opposite direction an angular distance substantially equal to the angular width of a tooth on said ratchet wheel irrespective of any actuation of said second electromagnetically-operated element,

(r) said second electromagnetically-operated element acting, whenever it is actuated, to effect actuation of said escapement mechanism, and thereby enable said spring to rotate said shaft in said one direction relative to said escapement wheel an angular distance substantially equal to the angular Width f a tooth on said ratchet wheel irrespective of any actuation of the first said electromagnetically-operated element,

(s) said stop limiting the extent to which said second electromagnetically-operated element can move said second pawl, and thereby keeping said second pawl from advancing said ratchet wheel an angular distance as great as the sum of the angular widths of two teeth on said ratchet wheel,

(t) said stop normally holding said second pawl in such intimate engagement with said ratchet wheel that said ratchet wheel and said rotatable member and said escapement wheel normally are held against rotation in either direction.

5. A stepping motor as claimed in claim 4 wherein said stop is stationary and has an inclined end, said second pawl having an inclined end that normally engages said inclined end of said stop and is thereby normally held in said intimate engagement with said ratchet wheel.

6. A stepping motor as claimed in claim 1 wherein said second electromagnetically-operated element selectively moves a pin against said escapement lever to move said escapement lever relative to said escapement wheel, said pin being rounded and being generally in register with the axis of said shaft to minimize the frictional forces between said pin and said escapement lever.

7. A stepping motor as claimed in claim 1 wherein said second electromagneticallyoperated element selectively moves a pin against said escapement lever to move said escapement lever relative to said escapement wheel, said pin engaging said escapement lever intermediate the ends of said escapement lever to provide a multiplying action for said escapement lever.

References Cited MILTON O. HIRSHFIELD, Primary Examiner. D. F. DUGGAN, Assistant Examiner. 

1. A STEPPING MOTOR THAT COMPRISES: (A) A BASE, (B) A SHAFT THAT IS ROTATABLY SUPPORTED BY SAID BASE, (C) SAID SHAFT BEING ROTATABLE IN ONE DIRECTION RELATIVE TO SAID BASE AND ALSO BEING ROTATABLE IN THE OPPOSITE DIRECTION RELATIVE TO SAID BASE, (D) MEANS BIASING SAID SHAFT FOR ROTATING IN SAID ONE DIRECTION RELATIVE TO, SAID BASE, (E) A ROTATABLE MEMBER THAT IS MOUNTED ON, AND THAT CAN ROTATE RELATIVE TO, SAID ROTATABLE SHAFT, (F) AN ESCAPEMENT WHEEL THAT IS ROTATABLE WITH SAID ROTATABLE MEMBER, (G) A RATCHET WHEEL THAT IS ROTATABLE WITH SAID ROTATABLE MEMBER, (H) A PAWL THAT IS MOUNTED ADJACENT SAID RATCHET WHEEL AND THAT PREVENTS ROTATION OF SAID RATCHET WHEEL, AND HENCE OF SAID ROTATABLE MEMBER AND ESCAPEMENT WHEEL, IN SAID ONE DIRECTION BUT THAT PERMITS ROTATION OF SAID RATCHET WHEEL, AND HENCE OF SAID ROTATABLE MEMBER AND ESCAPEMENT WHEEL, IN SAID OPPOSITE DIRECTION, (I) A SECOND PAWL THAT IS MOUNTED ADJACENT SAID RATCHET WHEEL, (J) AN ELECTROMAGNETICALLY-OPERATED ELEMENT THAT CAN BE ACTUATED TO CAUSE SAID SECOND PAWL TO ENGAGE A TOOTH ON SAID RATCHET WHEEL AND THEREBY ROTATE SAID RATCHET WHEEL, AND HENCE SAID ROTATABLE MEMBER AND ESCAPEMENT WHEEL, IN SAID OPPOSITE DIRECTION RELATIVE TO SAID BASE AN ANGULAR DISTANCE SUBSTANTIALLY EQUAL TO THE ANGULAR WIDTH OF SAID TOOTH, (K) THE FIRST SAID PAWL YIELDING TO PERMIT SAID SECOND PAWL AND SAID ELECTROMAGNETICALLY-OPERATED ELEMENT TO ROTATE SAID RATCHET WHEEL, AND HENCE SAID ROTATABLE MEMBER AND ESCAPEMENT WHEEL, IN SAID OPPOSITE DIRECTION, BUT THEREAFTER RETURNING TO ITS NORMAL POSITION TO BLOCK ROTATION OF SAID RATCHET WHEEL, AND HENCE OF SAID ROTATABLE MEMBER AND ESCAPEMENT WHEEL, IN SAID ONE DIRECTION, (L) A BRACKET THAT IS SECURED TO SAID SHAFT ADJACENT SAID ESCAPEMENT WHEEL AND THAT ROTATES WITH SAID SHAFT, (M) AN ESCAPEMENT LEVER THAT IS ROTATABLY SECURED TO SAID BRACKET AND THAT ROTATES WITH SAID BRACKET AND SAID SHAFT, (N) ONE PORTION OF SAID ESCAPEMENT LEVER NORMALLY BEING IN ENGAGEMENT WITH SAID ESCAPEMENT WHEEL BUT BEING MOVABLE OUT OF ENGAGEMENT WITH SAID ESCAPEMENT WHEEL AS ANOTHER PORTION OF SAID ESCAPMENT LEVER IS MOVED INTO ENGAGEMENT WITH SAID ESCAPEMENT WHEEL, 